Variable Density Groundwater Flow Simulation by Reduced Order Models

Effective management of coastal aquifers, vital for sustaining water resources and ecological balance, demands accurate and efficient simulation of seawater intrusion phenomena. This paper introduces a novel reduced-order model for seawater intrusion simulation, merging proper orthogonal decomposition (POD) with a finite difference approach. Addressing the computational challenges inherent in coupled partial differential equations governing density-dependent flow and solute transport, the proposed model offers a streamlined solution with enhanced computational efficiency. By projecting the system of equations onto a reduced set, POD facilitates the creation of smaller linear equation systems, ensuring rapid computation without compromising accuracy. Benchmarking against established codes like SEAWAT validates the model's efficacy for Elder and Henry's problems. The study demonstrates the potential of POD in advancing coastal groundwater management, offering a fast tool, which could be used for simulation-optimization models as well as sensitivity and uncertainty analysis models.